Does Grass Seed Expire?
Grass seed can go bad at some point, depending on the weather, storage climate, and methods used. The rate of germination of grass seeds decreases with age, so old grass seeds can yield disappointing results. The expiration date on the box is only for reference; seeds can still be viable after that date.
How Long Can You Store Grass Seed?
The shelf life of grass seed has a two- to the three-year expiration date, according to the Scotts Company. It's safer to use grass seed that's less than a year old. Seed storage varies by seed type, with ryegrass seed lasting up to 5 years if properly stored.
How Will I Know If My Seed Has Expired?
Expired grass seeds can be identified in a variety of ways. Even the package's expiration date is a guess. Check closely at the seed to see if there are any fungus spots or discoloration. Check for clumpy, moist areas and smell the seed and see if it has any unusual or foul odors.
How to store grass seed correctly?
It's important to learn how to properly store grass seed before sowing it. By storing your grass seeds in the right conditions and containers you can expand their lifespan and keep them fresher for longer.
Storing grass seeds also depends partially on when the seed's harvesting time is and how the seeds are handled. Internal moisture within the seeds may cause a shorter lifespan as well as damage to the seed coat from handling.
Seeds should be kept dry and prevented from absorbing too much moisture that can cause fungal issues and decrease their viability. General humidity for storage should not exceed 60%.
Containers should be suitable for the seed type and be kept well sealed to keep internal moisture levels and not introduce extra moisture from the outside.
Keep your grass seeds in a well-ventilated area that is not densely stacked as grass seeds need constant airflow to stay fresh and to prevent mold. Grass seeds go bad quickly in enclosed, damp, clumpy storage places.
Most grass seeds need temperatures that are not too hot and that will also not be cold enough to cause freezing. Make sure to keep grass seeds in a cool area that will keep their temperature reasonably constant. As a best practice, store your grass seeds below 60 °F (source).
Storing left-over grass seeds
You may not use an entire bag of seed all at once, and here we recommend that you use the right type of packaging to store leftover seed.
A cloth sack or a burlap bag should do the trick as they both allow good airflow.
To limit moisture some say that placing a container with baking soda inside the bag can eliminate some of the extra moisture.